Micro-fuel cell sensor apparatus and method

A sensor for measuring partial hydrogen pressure in gas streams, comprising:

• a housing;
• a sensing element comprising first and second gas diffusing electrodes spaced from one another disposed in said housing;
• a fuel-cell spacer having an acidic electrolyte disposed between said first and second electrodes;
• a first gas permeable membrane disposed adjacent to said first electrode;
• and
• a second gas permeable membrane separating said second electrode from atmospheric air entering said housing to supply oxygen to said second electrode by natural diffusion of atmospheric air.

An apparatus for measuring partial hydrogen pressure in a gas stream, comprising:

• a housing;
• a micro-fuel cell sensor disposed in said housing;
• a cover member;
• said sensor comprising:
• a sensing element comprising first and second spaced gas diffusing electrodes spaced from one another;
• a fuel-cell spacer having an acidic electrolyte interposed between said first and second electrodes;
• a first gas permeable membrane spaced from said first electrode;
• and
• a second gas permeable membrane spaced from said second electrode to supply oxygen to the second electrode by natural diffusion of atmospheric air.

In a sensor having a housing, a sensing element including first and second gas diffusing electrodes spaced from one another, first and second gas permeable membranes spaced from said first and second electrodes, respectively, a method for measuring hydrogen content in an external gas stream comprising the steps of:

• mounting the housing to an assembly carrying the external gas stream;
• permitting the gas stream to diffuse through said first membrane, thereby effecting an electrochemical charging of said first electrode;
• permitting oxygen to diffuse through said second membrane to furnish oxygen at said second electrode, oxygen furnished at said second electrode exceeding an amount necessary for a stochiometric reaction with hydrogen in the external gas stream;
• electrically connecting said first and second electrodes by a resistance;
• and
• measuring the current flow created by the potential difference between said first and second electrodes to produce a sensor output.